xref: /openbmc/linux/drivers/devfreq/governor.h (revision ecd25094)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * governor.h - internal header for devfreq governors.
4  *
5  * Copyright (C) 2011 Samsung Electronics
6  *	MyungJoo Ham <myungjoo.ham@samsung.com>
7  *
8  * This header is for devfreq governors in drivers/devfreq/
9  */
10 
11 #ifndef _GOVERNOR_H
12 #define _GOVERNOR_H
13 
14 #include <linux/devfreq.h>
15 
16 #define to_devfreq(DEV)	container_of((DEV), struct devfreq, dev)
17 
18 /* Devfreq events */
19 #define DEVFREQ_GOV_START			0x1
20 #define DEVFREQ_GOV_STOP			0x2
21 #define DEVFREQ_GOV_INTERVAL			0x3
22 #define DEVFREQ_GOV_SUSPEND			0x4
23 #define DEVFREQ_GOV_RESUME			0x5
24 
25 #define DEVFREQ_MIN_FREQ			0
26 #define DEVFREQ_MAX_FREQ			ULONG_MAX
27 
28 /**
29  * struct devfreq_governor - Devfreq policy governor
30  * @node:		list node - contains registered devfreq governors
31  * @name:		Governor's name
32  * @immutable:		Immutable flag for governor. If the value is 1,
33  *			this govenror is never changeable to other governor.
34  * @get_target_freq:	Returns desired operating frequency for the device.
35  *			Basically, get_target_freq will run
36  *			devfreq_dev_profile.get_dev_status() to get the
37  *			status of the device (load = busy_time / total_time).
38  *			If no_central_polling is set, this callback is called
39  *			only with update_devfreq() notified by OPP.
40  * @event_handler:      Callback for devfreq core framework to notify events
41  *                      to governors. Events include per device governor
42  *                      init and exit, opp changes out of devfreq, suspend
43  *                      and resume of per device devfreq during device idle.
44  *
45  * Note that the callbacks are called with devfreq->lock locked by devfreq.
46  */
47 struct devfreq_governor {
48 	struct list_head node;
49 
50 	const char name[DEVFREQ_NAME_LEN];
51 	const unsigned int immutable;
52 	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
53 	int (*event_handler)(struct devfreq *devfreq,
54 				unsigned int event, void *data);
55 };
56 
57 extern void devfreq_monitor_start(struct devfreq *devfreq);
58 extern void devfreq_monitor_stop(struct devfreq *devfreq);
59 extern void devfreq_monitor_suspend(struct devfreq *devfreq);
60 extern void devfreq_monitor_resume(struct devfreq *devfreq);
61 extern void devfreq_interval_update(struct devfreq *devfreq,
62 					unsigned int *delay);
63 
64 extern int devfreq_add_governor(struct devfreq_governor *governor);
65 extern int devfreq_remove_governor(struct devfreq_governor *governor);
66 
67 extern int devfreq_update_status(struct devfreq *devfreq, unsigned long freq);
68 
69 static inline int devfreq_update_stats(struct devfreq *df)
70 {
71 	return df->profile->get_dev_status(df->dev.parent, &df->last_status);
72 }
73 #endif /* _GOVERNOR_H */
74